CN108608821B - Vehicle suspension system comprising negative stiffness device and control method thereof - Google Patents
Vehicle suspension system comprising negative stiffness device and control method thereof Download PDFInfo
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- CN108608821B CN108608821B CN201810295541.XA CN201810295541A CN108608821B CN 108608821 B CN108608821 B CN 108608821B CN 201810295541 A CN201810295541 A CN 201810295541A CN 108608821 B CN108608821 B CN 108608821B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/06—Characteristics of dampers, e.g. mechanical dampers
- B60G17/08—Characteristics of fluid dampers
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Abstract
The invention provides a vehicle suspension system comprising a negative stiffness device and a control method thereof, wherein the vehicle suspension system comprises a detection mechanism, a control unit and an execution mechanism; the actuating mechanism comprises a hydraulic pump, an electromagnetic valve a, an electromagnetic valve b, an electromagnetic valve c, an electromagnetic valve d and a negative stiffness device; the negative rigidity device comprises a left cylinder and a right cylinder; the left cylinder and the right cylinder are respectively and symmetrically arranged on two sides of the vehicle body. The left cylinder and the right cylinder respectively comprise a cylinder body, a piston and an elastic element; the elastic element is arranged in the cylinder body, and a push rod of the piston is hinged with the vehicle body; the bottom of the cylinder body is hinged with the chassis frame. When the vibration amplitude of the vehicle body is small, the suspension and the negative stiffness device are matched for use, so that the natural frequency of the vehicle can be reduced, and the running smoothness of the vehicle is improved. When the vibration amplitude of the vehicle body is large, the electronic control unit ECU actively controls the negative stiffness device to stop working, and the influence on the running smoothness of the vehicle is avoided. The negative stiffness device is flexible and adjustable in stiffness and can be adjusted in real time according to the driving road conditions, so that the smoothness of the vehicle is improved.
Description
Technical Field
The invention belongs to the technical field of vehicle suspensions, and particularly relates to a vehicle suspension system comprising a negative stiffness device and a control method thereof.
Background
Suspension is an important assembly in automobiles and it elastically couples the frame to the wheels, transfers forces and torques acting between the wheels and the frame, and cushions the impact force transmitted to the frame or body from rough road surfaces and reduces the resulting vibrations to ensure smooth driving of the automobile. The suspension has great influence on the performance of the whole vehicle, such as the smoothness, the operation stability and the like. In recent years, with the development of science and technology, people pay more and more attention to riding comfort, and the requirements on the suspension performance of automobiles are continuously increased. The negative stiffness device is matched with the suspension frame for use, the stiffness is quasi-zero by reducing the stiffness of the system, the natural frequency of the vehicle body can be greatly reduced without reducing the bearing capacity of the whole vehicle, and the running smoothness of the vehicle is improved. Existing
Some patents are described in patent application No. 94112123.2, which add a negative stiffness spring device to the leaf spring, which is simple and reliable, and reduces the natural frequency of the vehicle body when the vibration amplitude is small, thereby improving the smoothness of the vehicle. As also described in patent application No. 201320502510.x, a negative stiffness device is formed by working actions of the upper and lower swing arms, the springs and the like, is stable and reliable, and can play a role in attenuating vibration of a vehicle body. However, this device does not consider the adjustment of the initial state, and the negative rigidity device cannot ensure that the negative rigidity device does not affect the vehicle at the vehicle body equilibrium position, and cannot sufficiently exert the function of the negative rigidity device.
Disclosure of Invention
The invention aims to provide a vehicle suspension system comprising a negative stiffness device and a control method thereof, wherein the negative stiffness device is designed on the basis of an active suspension system, and the system achieves the state of quasi-zero stiffness by combining the negative stiffness coefficient of the negative stiffness with the positive spring coefficient of an air suspension, so that the inherent frequency of a vehicle body is greatly reduced, and the running smoothness of the vehicle is improved. Due to the existence of the negative stiffness device, the stiffness of the system can be reduced, and the vibration amplitude of the vehicle body can be further increased. Therefore, when the vibration amplitude of the vehicle body is large, the negative stiffness device needs to be stopped. When the negative stiffness device needs to be used again after being stopped, a power source is needed to restore the negative stiffness device to the initial state. The negative stiffness device has flexible and adjustable stiffness, is used together with the active suspension, adapts to various road conditions, and can reduce the natural frequency of the vehicle body when the vibration amplitude of the vehicle body is small, so that the natural frequency of the vehicle body is further reduced, and the running smoothness and stability of the vehicle are improved.
The technical scheme of the invention is as follows: a vehicle suspension system including a negative stiffness device includes a detection mechanism, a control unit, and an actuator;
the executing mechanism comprises a hydraulic pump, an electromagnetic valve a, an electromagnetic valve b, an electromagnetic valve c, an electromagnetic valve d and a negative stiffness device; the negative stiffness device comprises a left cylinder and a right cylinder; the left cylinder and the right cylinder are respectively and symmetrically arranged on two sides of the vehicle body; the left cylinder and the right cylinder respectively comprise a cylinder body, a piston and an elastic element; the elastic element is arranged in the cylinder body, the piston is arranged in the cylinder body, the end face of the piston is in contact with the elastic element, and a push rod of the piston is hinged with the vehicle body; the bottom of the cylinder body is hinged with a chassis axle; the hydraulic pump is respectively connected with the left cylinder and the right cylinder; the electromagnetic valve a is installed on a pipeline connected between an oil outlet of the right cylinder and the oil tank, the electromagnetic valve b is installed on a pipeline connected between an oil inlet of the right cylinder and an oil outlet of the hydraulic pump, the electromagnetic valve c is installed on a pipeline connected between an oil inlet of the left cylinder and an oil outlet of the hydraulic pump, and the electromagnetic valve d is installed on a pipeline connected between an oil outlet of the left cylinder and the oil tank;
the detection mechanism detects the height information of the vehicle body, the liquid pressure of the left cylinder and the liquid pressure of the right cylinder; the control unit is respectively connected with the detection mechanism, the electromagnetic valve a, the electromagnetic valve b, the electromagnetic valve c, the electromagnetic valve d and the hydraulic pump; the control unit receives a signal of the detection mechanism, judges the vibration amplitude of the vehicle body according to the height h of the vehicle body, when the vehicle body is at a balance position, the height of the vehicle body is h0, the maximum height of the vehicle body away from the balance position is delta h, when the height h of the vehicle body is between h 0-delta h and h0+ delta h, the vehicle body vibrates in small amplitude, the control unit controls the closing of the electromagnetic valve a and the electromagnetic valve d, the opening of the electromagnetic valve b, the opening of the electromagnetic valve c and the opening of the hydraulic pump, and the hydraulic pump pumps hydraulic oil to the left cylinder and the right; when the height h of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the vehicle body vibrates greatly, the control unit controls the electromagnetic valve a and the electromagnetic valve d to be opened, and hydraulic oil of the left cylinder and the right cylinder flows to the oil tank through the electromagnetic valve a and the electromagnetic valve d.
In the above scheme, the detection mechanism comprises a vehicle height sensor, a hydraulic sensor a and a hydraulic sensor b; the vehicle body height sensor is used for detecting vehicle body height information; the hydraulic sensor a is used for detecting the hydraulic pressure of the left cylinder; the hydraulic pressure sensor b is used to detect the hydraulic pressure of the right cylinder.
In the above scheme, the control unit is the ECU1, which includes an input module, a judgment module and an output module;
the input module is connected with the detection mechanism and used for receiving a vehicle body height signal and a liquid pressure signal of the detection mechanism; the judging module judges the vibration amplitude of the vehicle body according to the height of the vehicle body and sends an instruction to the output module, and the output module is connected with the executing mechanism and respectively controls the electromagnetic valve a, the electromagnetic valve b, the electromagnetic valve c, the electromagnetic valve d and the hydraulic pump to work.
In the scheme, the elastic element comprises an oil-gas diaphragm, high-pressure gas and hydraulic oil;
one end of the oil-gas diaphragm is provided with high-pressure gas, and the other end of the oil-gas diaphragm is provided with hydraulic oil.
In the scheme, the volume of the hydraulic oil pushed by the oil-gas diaphragm under the pressure of the high-pressure gas is V, the moving distance of the piston is d, and the relation between d and the volume V can be represented by a formula
Where S denotes the cross-sectional area of the piston.
In the scheme, the hydraulic pump is connected with the vehicle-mounted power supply, the electromagnetic relay is arranged between the hydraulic pump and the vehicle-mounted power supply, and the electromagnetic relay is connected with the control unit.
A method of controlling a suspension system of a vehicle including a negative stiffness device, comprising the steps of:
the detection mechanism detects the height information h of the vehicle body, the liquid pressure of the left cylinder and the liquid pressure of the right cylinder and transmits the height information h of the vehicle body, the liquid pressure of the left cylinder and the liquid pressure of the right cylinder to the control unit, and the control unit judges the vibration amplitude of the vehicle body according to the height of the vehicle body so as to judge whether the negative stiffness device needs to be released or operated;
initially, the control unit controls the electromagnetic valve a, the electromagnetic valve b, the electromagnetic valve c and the electromagnetic valve d to be closed; when the vehicle body bumps, the piston generates thrust on the vehicle body to promote the vehicle body to be far away from a balance position, when the vehicle body is at the balance position, the height of the vehicle body is h0, the maximum height of the vehicle body away from the balance position is delta h, when the height h of the vehicle body is between h 0-delta h and h0+ delta h, the vehicle body vibrates in small amplitude, the control unit controls the electromagnetic valve a and the electromagnetic valve d to be closed, the electromagnetic valve b, the electromagnetic valve c and the hydraulic pump are opened, and the hydraulic pump pumps hydraulic oil to the left cylinder and the right cylinder;
when the height h of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the vehicle body vibrates greatly, the control unit controls the electromagnetic valve a and the electromagnetic valve d to be opened, and hydraulic oil of the left cylinder and the right cylinder flows to the oil tank through the electromagnetic valve a and the electromagnetic valve d.
In the scheme, if h is greater than h0+ delta h, the vehicle body is judged to vibrate greatly, the maximum height which can be reached by the vehicle body is recorded as h1, the control unit controls the electromagnetic valve a and the electromagnetic valve d to be opened, hydraulic oil flows to the oil tank through the electromagnetic valve a and the electromagnetic valve d, the thrust of the hydraulic oil to the piston is 0, the negative stiffness device stops working, the observation period is started, and the negative stiffness device does not work in the observation period;
the vehicle body starts to move downwards after reaching the highest position, passes through the balance position and reaches the lowest point, the height of the vehicle body is h2, and if h2 is greater than h 0-delta h, the vehicle body is judged to leave the observation period; if h2< h0- Δ h, the vehicle body is judged to be still in the observation period, the next half period is considered, the height of the vehicle body reaching the highest point is recorded as h3, if h3< h0+ Δ h, the vehicle body leaves the observation period, if h3> h0+ Δ h, the vehicle body is judged to be still in the observation period, the following half period is considered, and the operation is repeated until the vehicle body leaves the observation period;
after leaving the observation period, the control unit judges that the negative stiffness device needs to work, at the moment, the control unit controls the electromagnetic valve a and the electromagnetic valve d to be closed, the electromagnetic valve b, the electromagnetic valve c and the hydraulic pump to be opened, and the hydraulic pump pumps the oil into the left cylinder and the right cylinder.
In the scheme, in the process that the hydraulic pump pumps the oil to the left cylinder and the right cylinder, when the vehicle body is in a balance position, the hydraulic pressure of the left cylinder and the hydraulic pressure of the right cylinder are p0, in the process that the negative stiffness device works, the height h of the vehicle body corresponds to a fixed hydraulic pressure p, in the process of pumping the oil, the control unit judges the size of the expected hydraulic pressure p ' at the height according to the height of the vehicle body, compares the difference between p ' and p according to the hydraulic pressure p detected by the detection mechanism, and when the difference between p ' and p is 0, the control unit judges that the oil pumping is finished.
In the scheme, if the oil pumping of the left cylinder and the oil pumping of the right cylinder are finished simultaneously, the control unit controls the hydraulic pump to be closed and controls the electromagnetic valve c and the electromagnetic valve b to be opened;
when the oil pumping of the left cylinder is finished first, the control unit controls the electromagnetic valve c to be closed, at the moment, the hydraulic pump continues to pump oil to the right cylinder, and when the oil pumping of the right cylinder is also finished, the control unit controls the electromagnetic valve b and the hydraulic pump to be closed;
when the oil pumping of the right cylinder is finished first, the control unit controls the electromagnetic valve b to be closed, at the moment, the hydraulic pump continues to pump oil to the left cylinder, and when the oil pumping of the left cylinder is also finished, the control unit controls the electromagnetic valve c and the hydraulic pump to be closed.
Compared with the prior art, the invention has the beneficial effects that: according to the adjustable negative stiffness device and the suspension system matched with the same, when the vibration amplitude of a vehicle body is small, the suspension is matched with the negative stiffness device for use, so that the inherent frequency of an automobile can be reduced, the running smoothness of the automobile is improved, when the vibration amplitude of the vehicle body is large, the electronic control unit ECU actively controls the negative stiffness device to not work, and the influence on the running smoothness of the automobile is avoided. Simple structure, easy design and low cost.
Drawings
FIG. 2 is a logic diagram for determining the ECU according to the present invention;
FIG. 3 is a schematic diagram of an electronic control system according to the present invention;
fig. 4 is a graph of stiffness-displacement characteristics according to the present invention.
In the figure, 1, ECU; 2. a body height sensor; 3. a hinge; 4. a hydraulic pressure sensor a; 5. a chassis axle; 6. a vehicle body; 7. an air suspension; 8. a hydraulic pressure sensor b; 9. a right cylinder; 10. nitrogen gas; 11. an oil gas diaphragm; 12. a cylinder wall; 13. hydraulic oil; 14. a piston; 15. an electromagnetic valve a; 16. a solenoid valve b; 17. a hydraulic pump; 18. an electromagnetic relay; 19. an oil tank; 20. a power source; 21. a solenoid valve c; 22. a solenoid valve d; 23. and (4) a left cylinder.
Detailed Description
The present invention will be described in further detail with reference to the following drawings and detailed description, but the scope of the present invention is not limited thereto.
Fig. 1 shows an embodiment of a vehicle suspension system including a negative stiffness device according to the present invention, which includes a sensing mechanism, a control unit, and an actuator.
The detection mechanism comprises a vehicle height sensor 2, a hydraulic pressure sensor a4 and a hydraulic pressure sensor b 8. The body height sensor 2 is used for sensing body height information; the hydraulic pressure sensor a4 and the hydraulic pressure sensor b8 are respectively installed in the left cylinder 23 and the right cylinder 9, and the hydraulic pressure sensor a4 is used for detecting the hydraulic pressure of the left cylinder 23; the hydraulic pressure sensor b8 is used to detect the hydraulic pressure of the right cylinder 9. Initially, the air suspension 7 adjusts the height of the vehicle body 6 to enable the left cylinder 23 and the right cylinder 9 to be perpendicular to the vehicle body 6, the hydraulic pressure of the left cylinder 23 and the hydraulic pressure of the right cylinder 9 are the largest, the size of the hydraulic pressure p in the cylinders determines the rigidity displacement characteristic of the whole system, a proper amount of oil is filled into the cylinders to enable the hydraulic pressure to be p0, in this state, the negative rigidity device and the air suspension 7 are used in parallel, the system has good rigidity displacement characteristic, and the rigidity displacement characteristic of the system is shown in fig. 4. Where h0 is the height of the vehicle body 6 from the ground when the vehicle body 6 is in the equilibrium position. When the height of the vehicle body is between h 0-delta h and h0+ delta h, the negative rigidity and the air suspension system work together, so that the rigidity of the vehicle body is quasi-zero, and the running smoothness of the vehicle is improved; when the height of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the negative stiffness device does not work, the stiffness characteristic of the system is determined by the air suspension, and the smoothness of the vehicle in running cannot be reduced.
The actuator includes a power source 20, a hydraulic pump 17, an electromagnetic relay 18, a solenoid valve a15, a solenoid valve b16, a solenoid valve c21, a solenoid valve d22, and a negative stiffness device.
The negative stiffness means comprises a left cylinder 23 and a right cylinder 9; the left cylinder 23 and the right cylinder 9 are respectively and symmetrically arranged on two sides of the vehicle body 6; the left cylinder 23 and the right cylinder 9 both comprise cylinder bodies, pistons 14 and elastic elements; the elastic element is arranged in the cylinder body, the piston 14 is arranged in the cylinder body, the end face of the piston 14 is in contact with the elastic element, and a push rod of the piston 14 is hinged with the vehicle body 6; the bottom of the cylinder is hinged with a chassis axle 5. Preferably, the elastic element comprises an oil-gas diaphragm 11, high-pressure gas and hydraulic oil 13; one end of the oil-gas diaphragm 11 is provided with high-pressure gas, and the other end of the oil-gas diaphragm is provided with hydraulic oil 13. Preferably, the high pressure gas is nitrogen 10.
The power supply 20 is a vehicle-mounted power supply and is used for supplying power to the hydraulic pump 17; the hydraulic pump 17 is used for pumping oil from the oil tank 19 to the left cylinder 23 and the right cylinder 9; the electromagnetic valve is used for controlling the on-off of an oil path through opening and closing, the electromagnetic valve a15 is installed on a pipeline connected between an oil outlet of the right cylinder 9 and the oil tank 19, the electromagnetic valve b16 is installed on a pipeline connected between an oil inlet of the right cylinder 9 and an oil outlet of the hydraulic pump 17, the electromagnetic valve c21 is installed on a pipeline connected between an oil inlet of the left cylinder 23 and an oil outlet of the hydraulic pump 17, and the electromagnetic valve d22 is installed on a pipeline connected between an oil outlet of the left cylinder 23 and the oil tank 19; the electromagnetic relay 18 is arranged between the vehicle-mounted power supply 20 and the hydraulic pump 17 and is used for controlling whether the power supply supplies power to the hydraulic pump 17 to enable the hydraulic pump 17 to work; the left cylinder 23 and the right cylinder 9 respectively comprise a cylinder wall 12, a piston 14, an oil-gas diaphragm 11, nitrogen 10 and hydraulic oil 13. The pressure of the nitrogen 10 is high, and the oil-gas diaphragm 11 is pushed to push the hydraulic oil 13 to move; the oil-gas diaphragm 11 is used for separating the nitrogen 10 from the hydraulic oil 13 and transmitting the force between the nitrogen 10 and the hydraulic oil 13; the hydraulic oil 13 is used for pushing the piston 14 to move; the piston 14 is used for transmitting the thrust of the hydraulic oil 13 to the vehicle body 6 and acts together with the air suspension 7, so that the rigidity is quasi-zero, and the running smoothness of the vehicle is improved. The air suspension 7 initially adjusts the height of the vehicle body so that the pistons 14 of the left and right cylinders 23, 9 act vertically on the vehicle body 6. The cylinder walls 12 of the left cylinder 23 and the right cylinder 9 are respectively connected to the chassis axle 5 through hinges 3, the pistons 14 of the left cylinder 23 and the right cylinder 9 are respectively connected to the vehicle body 6 through hinges 3, and when the automobile is installed, the left cylinder 23 and the right cylinder 9 need to be in the same straight line when the automobile is in a balance position. The left cylinder 23 and the right cylinder 9 comprise a large oil chamber and a small oil chamber, the deformation amount of the oil-gas diaphragm 11 is limited, the volume V of the hydraulic oil 13 pushed by the oil-gas diaphragm 11 under the pressure of nitrogen 10 is limited, and the relation between the moving distance d of the piston 14 and the volume V can be represented by a formula
Where S represents the cross-sectional area of the piston 14. By using a small oil chamber, the size of the cross-sectional area S of the piston 14 can be reduced, thereby increasing the distance that the piston 14 travels so that the negative stiffness device always acts to generate thrust on the vehicle body 6 when in operation.
The control unit is an ECU1, which, as shown in fig. 3, comprises three modules: the device comprises an input module, a judgment module and an output module. The input module is used for receiving a vehicle body height signal and a liquid pressure signal detected by the detection mechanism. The output module mainly sends signals to the electromagnetic relay 18, the electromagnetic valve a15, the electromagnetic valve b16, the electromagnetic valve c21 and the electromagnetic valve d22 to control the on-off of the electromagnetic relay; the judging module judges the vibration amplitude of the vehicle body 6 according to the height of the vehicle body, so as to judge whether the negative stiffness device needs to be released or operated.
When the vehicle body 6 is in the balance position, the vehicle body height is recorded as h0, and when the vehicle body height h is between h 0-delta h and h0+ delta h, the vehicle body 6 is indicated to vibrate in small amplitude; when the height h of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the vehicle body 6 is indicated to vibrate greatly, the size of delta h is known from passenger and driver riding comfort experience, and when the negative rigidity device works, the height change of the vehicle body is in a quasi-zero interval in a rigidity displacement diagram. Initially, the input module controls the solenoid valve a15, the solenoid valve b16, the solenoid valve c21 and the solenoid valve d22 to be closed, when the vehicle body 6 bumps and moves upwards relative to the wheels from a balance position, the vehicle body moves downwards, the piston 14 generates thrust on the vehicle body 6 under the action of hydraulic pressure to promote the vehicle body 6 to be away from the balance position, at the moment, the vehicle body height sensor 2 detects the vehicle body height h, and if h < h0+ Δ h and h > h0- Δ h, it is judged that the vehicle body 6 vibrates in a small amplitude, and the negative stiffness device continues to work.
If h is greater than h0+ Δ h, it is determined that the vehicle body 6 is vibrating greatly, the use of the negative stiffness device needs to be released, the maximum height that the vehicle body 6 can reach is h1, at this time, the output module sends signals to the solenoid valve a15 and the solenoid valve d22 to open the solenoid valves, and the hydraulic oil 13 flows to the oil tank 19 through the solenoid valve a15 and the solenoid valve d 22. At this time, the thrust of the hydraulic oil 13 to the piston 14 is close to 0, the negative stiffness device stops operating, and then an observation period is entered in which the negative stiffness device does not operate.
When the vehicle body 6 reaches the highest position, it will start moving downward, and cross the equilibrium position to reach the lowest point, and the height of the vehicle body is recorded as h 2. If h2 is more than h 0-delta h, judging that the observation period is left; if h2< h0- Δ h, the next half cycle is considered in the observation period, the height of the vehicle body 6 reaching the highest point is recorded as h3, if h3< h0+ Δ h, the vehicle body is judged to leave the observation period, and if h3> h0+ Δ h, the vehicle body is judged to be in the observation period, the following half cycle is considered, and the process is repeated until the vehicle body is judged to leave the observation period. The ECU determination logic is shown in fig. 2.
When the observation period has elapsed, the ECU1 decision module determines that the negative stiffness device needs to operate, and at this time, the output module sends a signal to solenoid a15 and solenoid d22 to close them. The solenoid valve b16 and the solenoid valve c21 are connected by sending signals, and the solenoid relay 18 is connected by sending signals. The hydraulic pump 17 is powered by the power source 20, and the hydraulic pump 17 pumps oil into the left cylinder 23 and the right cylinder 9.
Since the hydraulic pressure p0 is obtained when the vehicle body 6 is in the equilibrium position, the vehicle body height h corresponds to a fixed hydraulic pressure p during the operation of the negative stiffness device. In the oil pumping process, the judging module judges the size of the expected hydraulic pressure p' under the height according to the height of the vehicle body, compares the difference between the hydraulic pressure p detected by the hydraulic pressure sensor and the difference between the hydraulic pressure p and the hydraulic pressure p detected by the hydraulic pressure sensor, and judges the completion of oil pumping when the difference between the hydraulic pressure p and the hydraulic pressure p is 0.
If the oil pumping of the left cylinder 23 and the right cylinder 9 is finished simultaneously, the output module sends signals to the electromagnetic relay 18 to be disconnected and sends signals to the electromagnetic valve c16 and the electromagnetic valve b21 to be combined, and the negative stiffness device works normally. In actual installation, the lengths of oil pipes from the left cylinder 23 and the right cylinder 9 to the hydraulic pump 17 are not necessarily the same, the oil resistance is not necessarily the same, and in the oil pumping process, the hydraulic pressures of the left cylinder 23 and the right cylinder 9 are not necessarily the same, and one of the left cylinder 23 and the right cylinder 9 may be pumped first. When the left cylinder 23 finishes pumping first, the ECU output module sends a signal to the solenoid valve c21 to close it. At this time, the hydraulic pump 17 pumps the oil to the right cylinder 9, and when the oil pumping of the right cylinder 9 is completed, the ECU1 output module sends a signal to the electromagnetic valve b16 to close and simultaneously sends a signal to the electromagnetic relay 18 to open, the hydraulic pump 17 stops operating, and the negative stiffness device operates normally. When the right cylinder 9 pumping is completed first, the ECU1 output module sends a signal to solenoid valve b16 to close. At this time, the hydraulic pump 17 pumps oil to the left cylinder 23, and when the oil pumping to the left cylinder 23 is completed, the ECU1 output module sends a signal to the electromagnetic valve c21 to close and simultaneously sends a signal to the electromagnetic relay 18 to open, so that the hydraulic pump 17 stops operating, and the negative stiffness device operates normally.
The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.
Claims (9)
1. A vehicle suspension system including a negative stiffness device comprising a sensing mechanism, a control unit and an actuator;
the actuating mechanism comprises a hydraulic pump (17), an electromagnetic valve a (15), an electromagnetic valve b (16), an electromagnetic valve c (21), an electromagnetic valve d (22) and a negative stiffness device; the negative stiffness device comprises a left cylinder (23) and a right cylinder (9); the left cylinder (23) and the right cylinder (9) are respectively and symmetrically arranged on two sides of the vehicle body (6); the left cylinder (23) and the right cylinder (9) both comprise cylinder bodies, pistons (14) and elastic elements; the elastic element is arranged in the cylinder body, the piston (14) is installed in the cylinder body, the end face of the piston (14) is in contact with the elastic element, and a push rod of the piston (14) is hinged with the vehicle body (6); the bottom of the cylinder body is hinged with a chassis axle (5); the elastic element comprises an oil-gas diaphragm (11), high-pressure gas and hydraulic oil (13); one end of the oil-gas diaphragm (11) is provided with high-pressure gas, and the other end of the oil-gas diaphragm is provided with hydraulic oil (13); the hydraulic pump (17) is respectively connected with the left cylinder (23) and the right cylinder (9); the electromagnetic valve a (15) is installed on a pipeline connected between an oil outlet of the right cylinder (9) and the oil tank (19), the electromagnetic valve b (16) is installed on a pipeline connected between an oil inlet of the right cylinder (9) and an oil outlet of the hydraulic pump (17), the electromagnetic valve c (21) is installed on a pipeline connected between an oil inlet of the left cylinder (23) and an oil outlet of the hydraulic pump (17), and the electromagnetic valve d (22) is installed on a pipeline connected between an oil outlet of the left cylinder (23) and the oil tank (19);
the detection mechanism detects the height information of the vehicle body, the liquid pressure of the left cylinder (23) and the liquid pressure of the right cylinder (9); the control unit is respectively connected with the detection mechanism, the electromagnetic valve a (15), the electromagnetic valve b (16), the electromagnetic valve c (21), the electromagnetic valve d (22) and the hydraulic pump (17); the control unit receives a signal of the detection mechanism, judges the vibration amplitude of the vehicle body (6) according to the vehicle body height h, when the vehicle body (6) is at a balance position, the vehicle body height is h0, the maximum height of the vehicle body (6) away from the balance position is delta h, when the vehicle body height h is between h 0-delta h and h0+ delta h, the vehicle body (6) vibrates in a small amplitude, the control unit controls the electromagnetic valve a (15) and the electromagnetic valve d (22) to be closed, the electromagnetic valve b (16), the electromagnetic valve c (21) and the hydraulic pump (17) to be opened, and the hydraulic pump (17) pumps hydraulic oil to the left cylinder (23) and the right cylinder (9); when the height h of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the vehicle body (6) vibrates greatly, the control unit controls the electromagnetic valve a (15) and the electromagnetic valve d (22) to be opened, and hydraulic oil of the left cylinder (23) and the right cylinder (9) flows to the oil tank (19) through the electromagnetic valve a (15) and the electromagnetic valve d (22).
2. The vehicle suspension system incorporating a negative stiffness device according to claim 1 wherein the sensing mechanism includes a body height sensor (2), a hydraulic pressure sensor a (4) and a hydraulic pressure sensor b (8); the vehicle height sensor (2) is used for detecting vehicle height information; the hydraulic sensor a (4) is used for detecting the hydraulic pressure of the left cylinder (23); the hydraulic pressure sensor b (8) is used for detecting the hydraulic pressure of the right cylinder (9).
3. The vehicle suspension system incorporating a negative stiffness device according to claim 1 wherein the control unit is an ECU (1) including an input module, a determination module and an output module;
the input module is connected with the detection mechanism and used for receiving a vehicle body height signal and a liquid pressure signal of the detection mechanism; the judgment module judges the vibration amplitude of the vehicle body (6) according to the height of the vehicle body and sends an instruction to the output module, and the output module is connected with the execution mechanism and respectively controls the work of the electromagnetic valve a (15), the electromagnetic valve b (16), the electromagnetic valve c (21), the electromagnetic valve d (22) and the hydraulic pump (17).
4. The vehicle suspension system including negative stiffness means according to claim 1 wherein the hydro-pneumatic diaphragm (11) is adapted to move hydraulic oil (13) under high pressure gas pressure by a volume V, the piston (14) is adapted to move a distance d, and the relationship between d and the volume V is formulated as
Wherein S represents the cross-sectional area of the piston (14).
5. Vehicle suspension system comprising a negative stiffness device according to claim 1, characterized in that the hydraulic pump (17) is connected to an on-board power supply (20), an electromagnetic relay (18) is mounted between the hydraulic pump (17) and the on-board power supply (20), said electromagnetic relay (18) being connected to the control unit.
6. A method of controlling a suspension system of a vehicle incorporating a negative stiffness device according to claim 1, comprising the steps of:
the detection mechanism detects the height information h of the vehicle body, the liquid pressure of the left cylinder (23) and the liquid pressure of the right cylinder (9) and transmits the height information h of the vehicle body, the liquid pressure of the left cylinder (23) and the liquid pressure of the right cylinder (9) to the control unit, and the control unit judges the vibration amplitude of the vehicle body (6) according to the height of the vehicle body so as to judge whether the negative stiffness device needs to be released or operated;
initially, the control unit controls the solenoid valve a (15), the solenoid valve b (16), the solenoid valve c (21) and the solenoid valve d (22) to be closed; when the vehicle body (6) bumps, the piston (14) generates thrust on the vehicle body (6) to promote the vehicle body (6) to be away from a balance position, when the vehicle body (6) is in the balance position, the height of the vehicle body is h0, the maximum height of the vehicle body (6) away from the balance position is delta h, when the height of the vehicle body is between h 0-delta h and h0+ delta h, the vehicle body (6) vibrates in a small amplitude, the control unit controls the electromagnetic valve a (15) and the electromagnetic valve d (22) to be closed, the electromagnetic valve b (16), the electromagnetic valve c (21) and the hydraulic pump (17) to be opened, and the hydraulic pump (17) pumps hydraulic oil to the left cylinder (23) and the right cylinder (9);
when the height h of the vehicle body is smaller than h 0-delta h or larger than h0+ delta h, the vehicle body (6) vibrates greatly, the control unit controls the electromagnetic valve a (15) and the electromagnetic valve d (22) to be opened, and hydraulic oil of the left cylinder (23) and the right cylinder (9) flows to the oil tank (19) through the electromagnetic valve a (15) and the electromagnetic valve d (22).
7. The control method of a vehicle suspension system incorporating a negative stiffness device according to claim 6, wherein if h > h0+ Δ h, it is determined that the vehicle body (6) is vibrating to a large extent, taking into account that the maximum height that the vehicle body (6) can reach is h1, the control unit controls the solenoid valve a (15) and the solenoid valve d (22) to open, hydraulic oil flows to the tank (19) through the solenoid valve a (15) and the solenoid valve d (22), the thrust of the hydraulic oil (13) against the piston (14) is 0, the negative stiffness device stops operating, and then, an observation period is entered, in which the negative stiffness device does not operate;
the vehicle body (6) starts to move downwards after reaching the highest position, passes through the balance position and reaches the lowest point, the height of the vehicle body is h2, and if h2 is greater than h 0-delta h, the vehicle body is judged to leave the observation period; if h2< h 0-delta h, the vehicle body (6) is judged to be still in the observation period, the next half period is considered, the height of the vehicle body (6) reaching the highest point is recorded as h3, if h3< h0+ delta h, the vehicle body is judged to leave the observation period, if h3> h0+ delta h, the vehicle body is judged to be still in the observation period, the next half period is considered, and the operation is repeated until the vehicle body is judged to leave the observation period;
when the observation period is left, the control unit judges that the negative stiffness device needs to work, at the moment, the control unit controls the electromagnetic valve a (15) and the electromagnetic valve d (22) to be closed, the electromagnetic valve b (16), the electromagnetic valve c (21) and the hydraulic pump (17) to be opened, and the hydraulic pump (17) pumps the oil into the left cylinder (23) and the right cylinder (9).
8. The control method of a suspension system for a vehicle including a negative stiffness apparatus according to claim 7, wherein during the process that the hydraulic pump (17) pumps the hydraulic fluid to the left cylinder (23) and the right cylinder (9), since the hydraulic pressure of the left cylinder (23) and the right cylinder (9) is p0 when the vehicle body (26) is in the balanced position, the vehicle body height h corresponds to a fixed hydraulic pressure p during the process that the negative stiffness apparatus is operated, the control unit determines the magnitude of a desired hydraulic pressure p ' at the height according to the vehicle body height during the process of pumping the hydraulic fluid, compares the difference between p ' and p according to the hydraulic pressure p detected by the detection mechanism, and determines that the pumping of the hydraulic fluid is completed when the difference between p ' and p is 0.
9. The control method of a suspension system for a vehicle including a negative stiffness apparatus according to claim 8, wherein if the left cylinder (23) and the right cylinder (9) pump oil at the same time, the control unit controls the hydraulic pump (17) to be closed and controls the solenoid valve c (16) and the solenoid valve b (21) to be opened;
when the oil pumping of the left cylinder (23) is finished first, the control unit controls the electromagnetic valve c (21) to be closed, at the moment, the hydraulic pump (17) continues to pump oil to the right cylinder (9), and when the oil pumping of the right cylinder (9) is also finished, the control unit controls the electromagnetic valve b (16) and the hydraulic pump (17) to be closed;
when the oil pumping of the right cylinder (9) is finished firstly, the control unit controls the electromagnetic valve b (16) to be closed, at the moment, the hydraulic pump (17) continues to pump oil to the left cylinder (23), and when the oil pumping of the left cylinder (23) is also finished, the control unit controls the electromagnetic valve c (21) and the hydraulic pump (17) to be closed.
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| CN110067828B (en) * | 2019-03-25 | 2021-08-03 | 江苏大学 | Quasi-zero rigidity vibration isolation system and vehicle |
| CN112963497B (en) * | 2021-02-22 | 2022-10-28 | 江苏大学 | Adjustable quasi-zero stiffness vibration isolator |
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| EP0127741A1 (en) * | 1983-04-11 | 1984-12-12 | DEUTSCHE FORSCHUNGSANSTALT FÜR LUFT- UND RAUMFAHRT e.V. | Suspension system for a motor vehicle |
| SU1174790A1 (en) * | 1984-03-20 | 1985-08-23 | Ленинградский Ордена Ленина Политехнический Институт Им.М.И.Калинина | Permanent-magnet dynamometer |
| CN106274331A (en) * | 2015-05-27 | 2017-01-04 | 上海汽车集团股份有限公司 | Torsion beam, torsion beam type suspension, automobile |
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